Adjustable keyboard support stand



FIG. 1 is a perspective view of the front, top and one side of an adjustable keyboard support stand, showing my new design;

FIG. 2 is a perspective view of the rear, bottom and an opposite side thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a side elevational view thereof; the opposite side being identical to that shown. 

The ornamental design for an adjustable support stand, as shown and described. 